If your not happy with the stock plenum then buy a greddy copy or the real deal or you can go custom. Forwad facing will make a highmount easier. If you wanted to really go 26 buy a single manifold and throw a t67 on it would be a wicked combo I recon. Iv been talking to drift mob a bit lately and they just use a 25 with a plenum on top of the bottom runners forward facing then stock manifold with a 90 to make the turbo top mount. They are making 300 to 330 kw its cheap and effective something to think about